., there was a report of gunfire at the nearby massachusetts institute of technology, m.i.t. at 10:30 p.m. an m.i.t. campus police officer was found shot to death in his vehicle. he was later identified as 26-year-old sean collier. and it wasn't over. now an armed carjacking of a black mercedes suv, its driver held hostage at gunpoint for half an hour. the gunmen would then take that mercedes suv on a wild and deadly ride from cambridge to watertown, massachusetts. >> side street on the right. >> as they sped through the streets the suspects shot at police and threw explosive devices from the speeding car. i police officer was seriously wounded. and in watertown, lindsay gaylord found themselves in the center of the storm. >> there were cops yelling get the "f" back, what are you guys doing? get away. >> it was surreal. it felt like a movie. >> as more than 200 rounds were fired, resident kayla depaul la called 911. >> i heard explosion after explosion and crouched down in my doorway and saw the bullet come from here to there. >> you saw it? >> i saw it happened. it was so sc